Customers would like to know what determines the hostname field value in UIM alarms.
What determines the hostname in UIM alarms? Will the alarm use hostname or IP address?
The probe usually determines the hostname, unless the probe cannot determine the hostname or resolve it, otherwise the NAS tries to resolve the host via NAS 'Name Services.'
Nas Name Services
In the UIM nas probe, if you select the Enable Name Services option, the IP-addresses of the sources sending alarms will be resolved to host names according to the rules defined on this screen. The IP-addresses (with corresponding host names) of all sources sending alarms will be listed under the Address Table sub-tab. By right-clicking an entry in the list, you may override the hostname with a name of your own choice. You may also add your own entries to the list. Entries can be 'locked.'
Generally, if a given probe sends IP address in the hostname field, (and this may be a probe function if it uses name resolution), then the NAS will "try" to find a hostname for it (via NAS Name services, which uses multiple methods of lookup and resolution, e.g., looking up robot names, nslookup, NETBIOS, etc).
If the probe sends a hostname, NAS will usually leave it alone (although sometimes this doesn't work as expected and it tries to translate hostnames to other hostnames).
If you find a discrepancy/inaccurate host/IP pair, old outdated entries, etc. in the NAS Names Services entries they can be deleted.
NAS Name Services can be configured to no longer translate a hostname to an IP address or another hostname - it will only translate IP addresses to names.
To activate this add the following key/value to the "setup" section of nas.cfg:
skip_non_ip_ns_lookup = yes